JPH05229965A - Production of tertiary olefin - Google Patents

Abstract

PURPOSE:To produce a high-purity tertiary olefin by catalytically cracking an alkyl tertiary alkyl ether. CONSTITUTION:An alkyl tertiary alkyl ether is catalytically cracked in the presence of a catalyst consisting of Si (Ti, Zr) (Mg, Ca) (Na, K, Cl, S) to produce a tertiary olefin. The effects are exhibited in high conversion efficiency of the raw material and high selectivity to tertiary olefin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for producing tertiary olefins.

[0002]

2. Description of the Related Art When an alkyl tertiary alkyl ether is decomposed in the presence of an acid catalyst, the corresponding tertiary olefin is mainly produced, as disclosed in JP-A-55-2695 and 57-57.
-134421, 59-10528, 59-1
There are many reports such as 57037 and JP-A-2-53739.

For example, methyl tertiary butyl ether (hereinafter referred to as MTBE) decomposes to give a tertiary product as a main product.
It produces isobutylene which is a primary olefin and methanol which is an alkyl alcohol, but also often produces a dimer, a trimer of isobutylene, dimethyl ether and the like as by-products. When the obtained isobutylene is used as an industrial raw material, it is necessary to remove by-products and purify it to high purity.

Therefore, the decomposition reaction of the alkyl tertiary alkyl ether is carried out at a high rate of change (the ratio of the reacted raw material to the supplied raw material), and the tertiary olefin and the alkyl alcohol are highly selected (generated relative to the reacted raw material). It is hoped that a method of obtaining the ratio of produced products) will be developed.

[0005]

The object of the present invention is to carry out a decomposition reaction of an alkyl tertiary alkyl ether at a high conversion rate and to obtain a tertiary olefin and an alkyl alcohol at a high selectivity. is there.

[0006]

SUMMARY OF THE INVENTION The present invention provides an alkyl tertiary
In the method for producing a corresponding tertiary olefin by decomposing a secondary alkyl ether, the decomposition reaction is performed by the composition formula Si.
_a X _b Y _c Z _d O _e (where Si and O represent silicon and oxygen, respectively, X is at least one element selected from the group consisting of titanium and zirconium, and Y is a group consisting of magnesium and calcium. Z is at least one element selected from the group consisting of sodium, potassium, chlorine and sulfur, where a, b, c, d and e are atoms of each element. Represents a ratio, and when a = 1, b = 0.001 to 10, c =
0.0001 to 5 and d = 0 to 1, and e is the number of oxygen atoms required to satisfy the valence of each component. ) In the method for producing a tertiary olefin, the reaction is carried out in the presence of a catalyst having a composition shown in FIG.

Specific examples of the alkyl tertiary alkyl ether used in the present invention include MTBE, methyl tertiary amyl ether (hereinafter referred to as MTAE), ethyl tertiary butyl ether (hereinafter referred to as ETBE) and ethyl tertiary. Amyl ether (hereinafter referred to as ETAE) and the like.

The tertiary olefins obtained in the present invention are isobutylene and methanol when MTBE is used as a raw material, isoprene and methanol in the case of MTAE, isobutylene and ethanol in the case of ETBE, and in the case of ETAE. Isoprene and ethanol.

The catalyst used in the present invention is a catalyst having the composition described above, and the starting material and preparation method of the catalyst are not particularly limited, and known ones can be used. Specific examples of the preparation method include precipitation method, coprecipitation method, kneading method,
A supporting method and the like can be mentioned. The shape of the catalyst may be any of a cylindrical molded product, a cylindrical molded product, a crushed product, a powder, a supported product and the like, and can be arbitrarily selected depending on the purpose.

Specific examples of the catalyst raw material used here include colloidal silica and water glass as a silicon source; titanium tetrachloride and the like as a titanium source; zirconium oxide chloride, zirconium nitrate and the like as a zirconium source; nitric acid as a magnesium source. Magnesium, magnesium sulfate and the like; examples of the calcium source include calcium nitrate and calcium sulfate. For sodium and potassium, it is preferable to use nitrates. Chlorine and sulfur can be introduced by using chloride or sulfate as a raw material.

The reaction method for carrying out the present invention is not particularly limited, and known methods can be used. Specific examples include a fixed bed system, a moving bed system, and a fluidized bed system, but the fixed bed system is preferable from the viewpoint of operation. The reaction conditions are not particularly limited, and conventionally known conditions are adopted. Usually, reaction temperature 150-400 ° C, LH
SV (volume ratio of liquid raw material supplied per hour to catalyst volume) 0.1 to 100 h ^-1 , reaction pressure is atmospheric pressure to 2
It is carried out at 0 kg / cm ² . Further, an inert gas such as nitrogen or helium, an organic compound, steam or the like may be entrained in the raw material gas.

[0012]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to the examples.

Example 1 200 g prepared by adding water to 95 g of colloidal silica (silica content 20%), 26.5 g of zirconium oxide chloride octahydrate and 2.4 g of magnesium nitrate hexahydrate.
A small excess of aqueous ammonia was added dropwise to an aqueous solution of ml to form a gel, and the resulting precipitate was washed and filtered, and then dried in a dryer.
A catalyst was prepared by pulverizing and molding a product dried at 10 ° C. overnight and calcining at 600 ° C.

The composition of the catalyst thus obtained is represented by the following formula: Si ₁ Zr _0.26 Mg _0.03 O _e Since the atomic ratio e of oxygen is a value naturally determined by the valences of other elements, it will be omitted below.

This catalyst was filled in a stainless steel reaction tube kept at 260 ° C., and MTBE as a raw material was charged with LHSV3.
The decomposition reaction was performed by supplying the vaporized MTBE to the reactor at h ⁻¹ and introducing the vaporized MTBE into the reactor. The analysis was performed by gas chromatography.

As a result, the rate of change in MTBE is 99.9.
%, The selectivity of isobutylene was 99.7%, the by-product of dimethyl ether was not observed, and methanol was obtained quantitatively.

Examples 2 to 11 The following catalysts were prepared according to Example 1.

Example 2: Si ₁ Zr _0.05 Mg _0.03 Example 3: Si ₁ Zr _0.05 Mg _0.05 Cl _0.005 Example 4: Si ₁ Zr _0.49 Mg _0.29 Example 5: Si ₁ Zr _0.49 Mg _0.49 S _0.005 Example 6: Si ₁ Ti _0.76 Mg _0.12 Example 7: Si ₁ Zr _0.49 Ca _0.07 Example 8: Si ₁ Ti _0.05 Zr _0.05 Mg _0.05 Example 9: Si ₁ Zr _0.1 Mg _0.1 K _0.05 Example 10: Si ₁ Zr _0.2 Mg _0.1 Na _0.05 Example 11: Si ₁ Zr _0.05 Mg _0.05 Ca _{0.05 A} reaction was carried out in the same manner as in Example 1 using these catalysts. The results are shown in Table 1.

[0019]

[Table 1]

Comparative Example 1 A catalyst having the composition represented by the following formula Si ₁ Zr _0.26 was obtained in the same manner as in Example 1 except that 2.1 g of magnesium nitrate hexahydrate was used. When a reaction was carried out in the same manner as in Example 1 using this catalyst, the MTBE change rate was 99.5% and the isobutylene selectivity was 97.2%.

[0021]

EFFECTS OF THE INVENTION According to the method of the present invention, the decomposition reaction of alkyl tertiary alkyl ether can be carried out at a high conversion rate, and the tertiary olefin important as an industrial raw material can be obtained at a high selectivity. The effect is extremely large.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C07C 1/20 11/18 8619-4H 31/04 6958-4H 31/08 6958-4H // C07B 61/00 300 (72) Inventor Hitoshi Takeda 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory

Claims (1)

[Claims] In a method for producing a corresponding tertiary olefin by decomposing an alkyl tertiary alkyl ether, the decomposition reaction is carried out by the composition formula Si _a X _b Y _c Z _d O _e (where Si and O
Respectively represent silicon and oxygen, X is at least one element selected from the group consisting of titanium and zirconium, Y is at least one element selected from the group consisting of magnesium and calcium, Z is sodium, potassium, At least one selected from the group consisting of chlorine and sulfur
Indicates the element of the seed. However, a, b, c, d and e represent the atomic ratio of each element, and when a = 1, b = 0.001 to
10, c = 0.0001 to 5 and d = 0 to 1, and e is the number of oxygen atoms required to satisfy the valence of each component. (3) A method for producing a tertiary olefin, characterized in that the reaction is carried out in the presence of a catalyst having a composition shown in (3).